scholarly journals FEM analysis of the plastic deformation of the regular arched asperities in the two-stage cold metal forming processes

2019 ◽  
Author(s):  
Leon Kukielka ◽  
Lukasz Bohdal ◽  
Jaroslaw Chodor ◽  
Katarzyna Gotowala ◽  
Pawel Kaldunski ◽  
...  
Author(s):  
A. D. Uchitel ◽  
Yu. A. Malinovskyi ◽  
G. V. Danilina ◽  
N. V. Voytenko ◽  
D. P. Rybak ◽  
...  

Purpose. Justification of the influence of pulsating dynamic loads in the surface layers of parts obtained by plastic deformation methods on the quality of finished products during cold rolling, knurling, running in, drawing and stamping. Research methodology. A schematization was adopted in which the workpiece or part is an anisotropic medium elastically bonded along the surface of the junction of external reinforced layers with the internal mass of the part. On the basis of the proposed physical model, conditions were found under which under the action of cyclic surface loads, violations of the integrity of the appearance of fracturing and waviness of external fibers in the process of strengthening the treatment of semi-finished products and parts are possible. Findings. The obtained data allows us to establish the frequency characteristics of the process of unstable parametric oscillations caused by nonlinear friction between the forming element and the workpiece (part), which lead to a deterioration in the quality of finished products. In addition, for the steady-state operating modes of machines for cold metal forming, the dependence of the amplitudes of deformation waves, as functions of the maximum pulsations of the “periodic” components of surface forces, was obtained, and measures were proposed to reduce vibroactivity in the area of tool interaction with the workpiece and machine parts for cold processing. Originality. It consists in formulating and solving the second dynamic problem for the surface layers of the workpiece at the interface of the processed layers and the workpiece array. Depending on the occurring periodic forces for the surface layers, the conditions of steady and unstable operation of the shaping tool and the whole machine for metal forming by pressure, as a whole, are determined. Practical value of the work lies in the fact that safe modes of operation of metal forming machines have been identified, conditions for improving the design of machines for cold metal forming have been created, under which the possibility of occurrence of parametric oscillations, as well as the reduction of vibratory activity of machines for cold metal forming in minimized whole. Keywords: running in, knurling, drawing, plastic deformation, roller, tool, workpiece, the amplitude of oscillations, load, excitation coefficient, steady amplitude, deformation wave.


2016 ◽  
Vol 716 ◽  
pp. 114-120 ◽  
Author(s):  
Sebastian Mróz ◽  
Piotr Szota ◽  
Teresa Bajor ◽  
Andrzej Stefanik

The paper presents the results of physical modelling of the plastic deformation of the Mg/Al bimetallic specimens using the Gleeble 3800 simulator. The plastic deformation of Mg/Al bimetal specimens characterized by the diameter to thickness ratio equal to 1 was tested in compression tests. The aim of this work was determination of the range of parameters as temperature and strain rate that mainly influence on the plastic deformation of Mg/Al bars during metal forming processes. The tests were carried out for temperature range from 300 to 400°C for different strain rate values. The stock was round 22.5 mm-diameter with an Al layer share of 28% Mg/Al bars that had been produced using the explosive welding method. Based on the analysis of the obtained testing results it has been found that one of the main process parameters influencing the plastic deformation the bimetal components is the initial stock temperature and strain rate values.


2021 ◽  
Author(s):  
Zhihui Gong ◽  
Mandeep Singh ◽  
Bohao Fang ◽  
Dongbin Wei

Abstract Springback compensation is critical in sheet metal forming. Advanced techniques have been adopted in the design stage of various sheet metal forming processes, e.g. stamping, some of which are for complex shaped products. However, the currently available numerical approaches are not always sufficiently accurate and reliable. To improve the accuracy of springback compensation, an enhanced hybrid springback compensation method named Springback Path – Displacement Adjustment (SP-DA) method has been developed in this study based on the well-known conventional displacement adjustment (DA) method. Its effectiveness is demonstrated using FEM analysis of low, medium and high strength steels adopted in automobile industry, in which a symmetrical model owning geometry complexity similar to an auto body panel was established. The results show this new enhanced SP-DA method is able to significantly improve the accuracy of springback compensation comparing to conventional displacement adjustment technique.


2021 ◽  
Vol 343 ◽  
pp. 04007
Author(s):  
Mihai Popp ◽  
Gabriela Rusu ◽  
Sever-Gabriel Racz ◽  
Valentin Oleksik

Single point incremental forming is one of the most intensely researched die-less manufacturing process. This process implies the usage of a CNC equipment or a serial robot which deforms a sheet metal with the help of a relatively simple tool that follows an imposed toolpath. As every cold metal forming process, besides the many given advantages it has also some drawbacks. One big drawback in comparison with other cold metal forming processes is the low accuracy of the deformed parts. The aim of this research is to investigate the sheet metal bending mechanism through finite element method analysis. The results shows that the shape of the retaining rings has a big influence over the final geometrical accuracy of the parts manufactured through single point incremental forming.


2020 ◽  
Vol 1003 ◽  
pp. 31-36
Author(s):  
Marko Vilotic ◽  
Li Hui Lang ◽  
Sergei Alexandrov ◽  
Dragisa Vilotic

Compared to conventional metal forming methods, processing by severe plastic deformation is mostly used to improve the mechanical properties and not for the shaping of a product. Processed material usually has an average crystal grain size of less than a micron and as a result, the material exhibits improvements in most of the mechanical properties, such as yield and ultimate tensile strength, microhardness, sufficiently high workability, good corrosion resistance, and implant biocompatibility and others. In this paper, a brief review of the processing by severe plastic deformation was presented, including the benefits, major methods, and the application. Additionally, a brief review of two methods made by authors was made.


2019 ◽  
Vol 29 ◽  
pp. 02012
Author(s):  
Mihaela Savin ◽  
Adrian Presura ◽  
Ionel Chirica

This paper presents the FEM analysis of plastic deformation of different steel panels using a spherical indenter. Two experiments were done: first on a simple steel panel and second on a stiffened steel panel, which were subjected to a static plastic deformation produced with help of a spherical indenter. The results of the practical test were compared with the results of numerical simulations, which were accomplished using ANSYS-Static Structural module. The tests were realized using an experimental stand based on a screw press mechanism. The tests consist in vertical displacement of the spherical bulb, which in this way deformed the panel leaning on the stand frame. During the tests were measured the force applied to the indenter, with help of an PLC500 force transducer, and the vertical displacement of the panel in the application point of force, with help of an HBM WA/300 displacement transducer. The results of calculations are presented below as: final deformed models and force-displacement diagrams with the comparison between experiment and numerical simulation. In conclusion of this research the compared results between the experiments and numerical simulations revealed that can be achieved accurate results using FEM analysis for plastic deformation problems, with proper parameters settings.


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